Future long-duration human missions to the Moon and Mars, which NASA is planning, present monumental logistical challenges. One of the key problems is ensuring adequate nutrition for astronauts during multi-year journeys, where cargo space is limited, and resupply opportunities are non-existent. Vitamins and other key nutrients have a limited shelf life and lose their effectiveness over time, which means that supplies brought from Earth may not be sufficient or effective. To overcome this hurdle, scientists are developing a revolutionary biomanufacturing technology – the creation of nutrients on demand, directly in space. At the heart of these efforts is a series of experiments called BioNutrients, which tests the ability of microorganisms to become miniature, self-sustaining factories of vital compounds for human health.

Microscopic factories for astronaut health

The initial step in this ambitious project was the BioNutrients-1 experiment, launched to the International Space Station (ISS) back in April 2019. During the nearly six-year research period, astronauts tested a system based on genetically modified baker's yeast (Saccharomyces cerevisiae), a microorganism that is safe and common in the human diet. Scientists at NASA's Ames Research Center in Silicon Valley designed a system in which dehydrated yeast and a powdered food source wait in special containers. Activation is simple: astronauts inject sterile water, which initiates the growth process. In the liquid environment, the yeast multiplies and, like a tiny factory, begins to produce beta-carotene and zeaxanthin. These are powerful antioxidants, otherwise present in vegetables like carrots and spinach, which are crucial for protecting the eyes from damage, a particularly important issue in the high-radiation space environment.

The astronauts did not consume the produced nutrients; instead, after 48 hours of incubation in a warm place, the samples were frozen and returned to Earth for detailed analysis. Scientists carefully studied the system's efficiency, the amount of yeast grown, and the concentration of the nutrients produced. One of the key goals of BioNutrients-1 was to test long-term viability. For this purpose, two types of yeast were used. The first was capable of forming spores – a dormant, extremely resilient form of life that can survive extreme conditions, including high radiation and long-term storage. It is expected that the spores could remain viable for at least five years, which is crucial for missions to Mars. The second type of yeast was in a vegetative, or metabolically active, form. Although a shorter shelf life was expected, this type is interesting because it is already commercially used in probiotic supplements and offers a broader range of possibilities for future modifications. Analyses of the samples returned to Earth showed outstanding results – some microorganisms remained capable of activation even after more than five years in space, confirming the robustness of the concept.

Evolution of the experiment: From rigid containers to flexible bags

Building on the successes of the first phase, BioNutrients-2 arrived at the ISS in November 2022. This sequel brought significant innovations, aimed at optimizing the system for the real conditions of long-duration spaceflights. The biggest change was in the hardware. Instead of relatively heavy and rigid containers, BioNutrients-2 used lightweight, flexible bags, similar to those used for packaging astronaut food. This redesign drastically reduced the mass and volume of the system, freeing up precious space and lowering launch costs.

At the same time, the "menu" of microorganisms was expanded. In addition to the two types of yeast from the first experiment, four new cultures were added. Two of them were bacteria used for yogurt production, one for kefir, and the last one was particularly interesting – a type of yeast bioengineered to produce follistatin. Follistatin is a protein that plays a key role in maintaining muscle mass because it inhibits the action of myostatin, a protein responsible for muscle breakdown. Muscle atrophy is one of the biggest health risks for astronauts in weightlessness, and the ability to produce a compound that could counteract this directly in space represents a potential revolution in space medicine. During 2023, the crew on the ISS successfully conducted two cycles of experiments with this new system, confirming its functionality and versatility.

The latest phase: Food safety and multifunctional yeast on the ISS

The latest chapter in the BioNutrients saga began recently, in August 2025, with the launch of the BioNutrients-3 experiment on the SpaceX CRS-33 mission. This phase represents a crucial step towards real-world application, with an emphasis on food safety and further increasing efficiency. The hardware is still based on flexible bags, but they now have a larger volume to allow for the testing of safety protocols on larger samples. This phase uses commercial starters for yogurt and kefir, as well as new, advanced yeast strains that have been genetically modified to produce multiple different nutrients within a single bag. This is a significant step forward in optimizing the process.

One of the most interesting innovations in BioNutrients-3 is a growth substrate for the microorganisms that is fully edible, although the astronauts will not be consuming it yet. This is preparation for future experiments where the products will be tested as an actual food source. In addition, an ingenious visual indicator for monitoring fermentation has been introduced. A natural pigment from red cabbage is added to the mixture, which changes color depending on the acidity (pH value). As the bacteria convert sugars into acid during yogurt and kefir fermentation, the mixture changes color from purple to pink. This provides astronauts with a simple, visual, and unmistakable way to track the progress of the process without the need for complex equipment.

Innovative technologies for the future of space travel

BioNutrients-3 also introduces several advanced technologies that are key to creating a self-sustaining nutrition system. One of them is the testing of an "electronic nose" (E-Nose), a sensor that simulates the human sense of smell with exceptional sensitivity. This device can detect volatile organic compounds released by pathogens or spoilage bacteria, providing a rapid and non-invasive method for checking food safety. Furthermore, astronauts will test the pasteurization process using existing equipment on the station – a food warmer. This will verify the possibility of destroying any remaining microorganisms after fermentation is complete to make the product safe for long-term storage and consumption. Finally, a re-culturing technique will also be demonstrated, where a small part of the finished yogurt is used to start a new batch, similar to how a sourdough starter is maintained. Mastering this technique would mean that the system could be maintained almost indefinitely with minimal initial supplies.

Broader reach: From space to the remote corners of Earth

Although primarily developed for the needs of astronauts, the technology behind the BioNutrients project has enormous potential on Earth as well. The ability to produce fresh nutrients, and even medicines, on demand and with minimal infrastructure could transform life in remote areas, disaster-stricken zones, or during long-term military operations where supply chains are unreliable. By developing microorganisms that can withstand long periods of inactivity and then be successfully reactivated, NASA is not only opening the door to deep space exploration but also creating solutions that could improve the health and quality of life for people across our planet.